# ol.clave.acme.solver.dns

Protocol53-backed DNS-01 Challenge Solver.

Applications explicitly select and construct one compatible Protocol53
Provider, then pass it to [`solver`](#solver). A selected Provider artifact supplies
Protocol53; Clave’s base runtime dependencies remain unchanged. Clave never
scans credentials or selects a Provider.

The application, Provider, or upstream DNS service must coordinate unsafe
concurrent mutations to the same RRset.

## solver

```clojure
(solver provider)
(solver provider opts)
```

Creates a DNS-01 Challenge Solver backed by `provider`.

The returned map contains only `:present`, `:wait`, and `:cleanup` functions.
Construction validates the Provider, OpenJDK’s `jdk.naming.dns` module, and
`opts` without performing Provider or DNS work.

Configured resolvers are trusted exclusively and in order. An empty resolver
vector uses JVM/system DNS without a public fallback. `:presentation-name`
supplies the complete absolute TXT Record Name for manual delegation; Clave
neither prefixes nor follows it for presentation.

Lease cancellation prevents new Provider and DNS work. Protocol53 invokes a
Provider synchronously, so cancellation cannot guarantee interruption of a
Provider call already in flight. If an append succeeds while cancellation
races it, `:present` returns the owned state so `:cleanup` can remove the
Stored Record under a fresh timeout.

Each JNDI DNS query uses a separate context capped at ten seconds and closes
that context when its effective Lease ends. Thread interruption alone is not
a supported DNS-query cancellation mechanism.

Options:

|     |     |     |
| --- | --- | --- |
| key | accepted value | default |
| `:ttl` | Non-negative integer DNS seconds | `0` |
| `:propagation-checks?` | Boolean | `true` |
| `:propagation-delay-ms` | Non-negative integer milliseconds | `0` |
| `:propagation-timeout-ms` | Positive integer milliseconds | `120000` |
| `:propagation-readiness` | `:all` or `:any` | `:all` |
| `:resolvers` | Vector of resolver address strings | `[]` |
| `:presentation-name` | Absolute TXT Record Name or `nil` | `nil` |

```clojure
(dns/solver dns-provider)
(dns/solver dns-provider {:ttl 120
                          :propagation-timeout-ms 300000})
```

[source,window=_blank](https://github.com/outskirtslabs/clave/blob/main/src/ol/clave/acme/solver/dns.clj#L14-L56)